The existence of dead angles of vision for the driver of a motor vehicle represents a potential collision risk with other vehicles entering in said dead angles, which has not yet been solved in a satisfactory way by the vision offered by the rear view mirrors mounted in the vehicle. Therefore, different alternatives have arisen regarding the viewing to cover said dead angles, based on different technologies, some of which are used to cover zones very close to the vehicle and generally lateral zones, as the ones based on the detection of the distortion of the earth's magnetic field, and others are used for the detection of vehicles approaching said driver's vehicle, normally from behind, and from rather long distances, using in those cases different types of devices are needed, as for example electro-optical devices or radars. The operation of this type of devices, used for detecting vehicles approaching from rather long distances, is what is intended to be enhanced with the present invention.
The patent application EP-A-0591743 describes a device for detecting relative positions between vehicles, by means of an electro-optical sensor, preferably based on CCD technology, associated with a casing of a rear view mirror, and being said electro-optical sensor associated with an electronic processing unit connected to a central information system of the vehicle, to which it sends processed signals, providing finally warning signals. The aim of this device is to warn the driver of the vehicle where this device is installed, through various signals (acoustic, luminous, etc.), of the possible collision risk with an approaching vehicle. Furthermore, it is stated the possibility of using said device for warning the driver of the approaching vehicle of the possible collision risk, by means of the activation of the emergency lights of the vehicle, or of its direction indicators.
The patent application WO-A-01/61371 of the same applicant describes, furthermore, a device for detecting the presence of objects similar to the previous one, however, in said case the detection device consists of a receiver of electromagnetic waves and a photo sensor, which transforms the received electromagnetic waves into electric signals. In this document, special reference is made to the followed methodology when acquiring and processing the images, once digitized and previously amplified, as well as to the different calculation algorithms susceptible to be used for generating warning signals similar to the ones generated by the aforementioned device.
Even though the offered proposals represent a great step forward regarding conduction security, avoiding therewith a great number of risk situations for the occupants of a vehicle in which these devices are installed, however, it is also true that in many cases these devices turn out to be disturbing for said occupants, as the devices generate a large number of false alarms, provoked by normal driving situations without being dangerous, but which situations are interpreted wrongly and confounded with dangerous approaching of other vehicles. This happens due to the fact that, when designing said devices there has not been borne in mind the irregular circumstances through which the vehicle may go through in real driving situations, and the complexity of adapting said device to such circumstances.
U.S. Pat. No. 6,226,571 proposes a device for monitoring the environment of a vehicle, being able to predict a road's geography, as for example its curvature radius, only through the route information of a vehicle and a relative position. The proposed device includes a radar system for detecting the presence of objects around the vehicle and for supplying information about the position of the objects in a predetermined system of coordinates of detection, a vehicle identifying device to, starting from the detected objects, classify the objects that are vehicles and are driving on the road, distinguishing them from other types of objects. The device also includes a predictive device of the road's geography to predict it on the base of the position of the circulating vehicles and the route information according to an exit signal of the radar system and an exit signal of the vehicles identifying device. Even though the device proposed by said document, to the contrary of the previous ones, considers more closely a real driving situation, and combines a detection system similar to the previous ones, in this case a radar, with another type of sensors, such as speed sensors, driving angle sensors, etc., the stated applications are different to the ones proposed by the present invention, as in said patent one of the final targets is to predict as fast and realistic as possible the road or way's geography on which the vehicle is circulating, especially regarding its curvature radius. Therefore, even though it is possible to control the accelerator and the brake of the vehicle automatically, in order to maintain an appropriate distance to the preceding vehicle, on the base of the obtained information through the radar and said sensors, and, furthermore, to generate a warning signal if the situation is dangerous, in said antecedent no reference is made at any moment to the use of the information regarding the road's geography in order to modify or adjust the detection area of the radar system, or even to enhance said detection in any way.
Therefore, it is necessary to cover the existing lacks in the state of the art regarding the operation of these kind of devices, bearing in mind the different circumstances a vehicle may go through in a real driving situation, adding to the system for detecting the presence of objects in a dead angle, another series of detecting devices of said circumstances, in order to enhance said detection of the presence of objects, and therefore avoid the undesired false alarms.